FIG. 1.

The actin cytoskeleton undergoes time-dependent rearrangement during spreading. Human lens epithelial cells (FHL124) were plated on fibronectin; allowed to spread for 15, 30, 60, and 120 min; and stained with phalloidin. (A) Cells attached and spread within 15 min. A prominent band of polymerized actin formed around the cell perimeter. (B) By 30 min, the peripheral band of actin began to reorganize into short radial stress fibers (arrowheads) and actin-containing transverse arcs (arrows), which crossed the radial fibers at right angles. (C) By 60 min, more than 90% of cells contained numerous, well-formed ventral stress fibers (arrows). (D) By 120 min, cell borders became sharply concave as cells appeared to contract and more than 95% of cells retained well-formed stress fibers (arrows), which often spanned the entire cell. Scale bar, 20 μm.